Just watched THE BODY SNATCHER (1945) again last nite, and I can't believe no one has mentioned Boris Karloff's Cabman John Gray yet. This is probably Karloff's greatest performance--he absolutely dominates the screen when he's on it, and you keep waiting for him to return when he's off it.

Want evil?

This guy takes the business end of a shovel to the head of a cute little lapdog who's faithfully watching over his master's grave! Rough stuff!